libc/test/src/stdio/ftell_test.cpp

   1 //===-- Unittests for ftell -----------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "hdr/stdio_macros.h"
  10 #include "src/stdio/fclose.h"
  11 #include "src/stdio/fopen.h"
  12 #include "src/stdio/fread.h"
  13 #include "src/stdio/fseek.h"
  14 #include "src/stdio/fseeko.h"
  15 #include "src/stdio/ftell.h"
  16 #include "src/stdio/ftello.h"
  17 #include "src/stdio/fwrite.h"
  18 #include "src/stdio/setvbuf.h"
  19 #include "test/UnitTest/Test.h"
  20
  21 class LlvmLibcFTellTest : public LIBC_NAMESPACE::testing::Test {
  22 protected:
  23   void test_with_bufmode(int bufmode) {
  24     constexpr char FILENAME[] = "testdata/ftell.test";
  25     // We will set a special buffer to the file so that we guarantee buffering.
  26     constexpr size_t BUFFER_SIZE = 1024;
  27     char buffer[BUFFER_SIZE];
  28     ::FILE *file = LIBC_NAMESPACE::fopen(FILENAME, "w+");
  29     ASSERT_FALSE(file == nullptr);
  30     ASSERT_EQ(LIBC_NAMESPACE::setvbuf(file, buffer, bufmode, BUFFER_SIZE), 0);
  31
  32     // Include few '\n' chars to test when |bufmode| is _IOLBF.
  33     constexpr char CONTENT[] = "12\n345\n6789";
  34     constexpr size_t WRITE_SIZE = sizeof(CONTENT) - 1;
  35     ASSERT_EQ(WRITE_SIZE, LIBC_NAMESPACE::fwrite(CONTENT, 1, WRITE_SIZE, file));
  36     // The above write should have buffered the written data and not have
  37     // trasferred it to the underlying stream. But, ftell operation should
  38     // still return the correct effective offset.
  39     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftell(file)), WRITE_SIZE);
  40
  41     off_t offseto = 5;
  42     ASSERT_EQ(0, LIBC_NAMESPACE::fseeko(file, offseto, SEEK_SET));
  43     ASSERT_EQ(LIBC_NAMESPACE::ftello(file), offseto);
  44     ASSERT_EQ(0, LIBC_NAMESPACE::fseeko(file, -offseto, SEEK_END));
  45     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftello(file)),
  46               size_t(WRITE_SIZE - offseto));
  47
  48     long offset = 5;
  49     ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, offset, SEEK_SET));
  50     ASSERT_EQ(LIBC_NAMESPACE::ftell(file), offset);
  51     ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, -offset, SEEK_END));
  52     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftell(file)), size_t(WRITE_SIZE - offset));
  53
  54     ASSERT_EQ(0, LIBC_NAMESPACE::fseek(file, 0, SEEK_SET));
  55     constexpr size_t READ_SIZE = WRITE_SIZE / 2;
  56     char data[READ_SIZE];
  57     // Reading a small amount will actually read out much more data and
  58     // buffer it. But, ftell should return the correct effective offset.
  59     ASSERT_EQ(READ_SIZE, LIBC_NAMESPACE::fread(data, 1, READ_SIZE, file));
  60     ASSERT_EQ(size_t(LIBC_NAMESPACE::ftell(file)), READ_SIZE);
  61
  62     ASSERT_EQ(0, LIBC_NAMESPACE::fclose(file));
  63   }
  64 };
  65
  66 TEST_F(LlvmLibcFTellTest, TellWithFBF) { test_with_bufmode(_IOFBF); }
  67
  68 TEST_F(LlvmLibcFTellTest, TellWithNBF) { test_with_bufmode(_IONBF); }
  69
  70 TEST_F(LlvmLibcFTellTest, TellWithLBF) { test_with_bufmode(_IOLBF); }